The following lists definitions of common
terms and acronym used on my highway and road photo pages and in my posts on the misc.transport.road newsgroup and various transportation-related mailing lists
and forums.

MnDOT - The standard abbreviation I use for the
Minnesota
Department of Transportation. The
StarTribune and several other newspapers across the state generally use this
form of abbreviation as well. MnDOT itself generally uses Mn/DOT (with a
forward slash).

MHD - Acronym for the Minnesota Highway Department.
MHD merged with other transportation-related state agencies to become MnDOT in
1976.

BPR - Bureau of Public Roads, the precursor to the
Federal Highway Administration.

MTC - Short for the Metropolitan Transit Commission, the
precursor to today's Metro Transit.

Metro - The "Metro" is a shortened term commonly
used by Minnesotans that refers to the Minneapolis/St. Paul (or "Twin Cities")
metropolitan area. Generally consisting of the counties of Anoka, Carver,
Dakota, Hennepin, Ramsey, Scott, and Washington. The U.S. Census Bureau
also includes Wright, Sherburne, Isanti, and Chisago Counties in Minnesota and
Pierce and St. Croix Counties in Wisconsin as part of the Twin Cities metro
area.

Outstate - The other part of Minnesota
besides the "Metro". "Outstate" is what Minnesotans call the rest of
Minnesota outside of the Twin Cities metro area.

MnDOT Districts and "Metro Division" - Part
of MnDOT's organization. MnDOT is split into 8 districts, each
representing a geographical area within the state. The "Outstate"
districts are numbered from 1 to 8 (5 is not used). "Metro Division" is a
specialized district, representing the original 7-county Twin Cities metro area
plus Chisago County. It was formed in the late 1980s by merging the old
Districts 5 (west metro) and 9 (east metro) into one entity. Recently,
MnDOT changed its name and simply calls it "Metro District" (to reflect that it
is an organizational district like the Outstate districts are).

CSAH - County State Aid Highway.
A specialized form of county route that is part of the state aid system.
County State Aid routes are eligible for funding from the County State Aid
Highway Fund, which Constitutionally receives funding from just over 1/4 of the
proceeds from the state's gas tax, vehicle registration fees, and part of the
motor vehicle sales tax.

MSAS - Municipal State Aid System. Similar to the
County State Aid system, this is a system of designated municipal streets in
those cities above 5,000 in population, that are not already on the state
highway or CSAH systems. Municipal streets on the MSAS are eligible for
funding from the Municipal State Aid Highway Fund, which Constitutionally
receives just under 9% of the state funds Constitutionally dedicated to the
state's highway fund.

IRC - MnDOT's Interregional Corridor system. A
system of the most important regional and interregional highways in the state,
comprising of corridors connecting regional centers to each other and the Twin
Cities metropolitan area outside of the I-494/I-694 Beltway. System
highways are designated into three categories: High-Priority Interregional
Corridor, Medium-Priority Interregional Corridor, or Regional Corridor. By
default, all Interstate highways outside of the I-494/I-694 Beltway are
High-Priority IRC corridors.

NHS - National Highway System. Approved by
Congress in 1995, the NHS is a system (designated by FHWA and the various state
DOTs) of major roads of national importance or significance. By default,
the Interstate and STRAHNET (routes of importance to defense policy...designated
by the Transportation Engineering Agency of the U.S. Army) systems are part of
NHS. Major interregional corridors and roads providing access to
multimodal facilities (such as ports, airports, or rail terminals) are also part
of the NHS.

AADT - Average Annual Daily Traffic

HCADT - Heavy Commercial Average Daily Traffic

Preservation Corridor - One of four long-range investment strategies
designated by MnDOT for a given highway corridor. "Preservation" corridors
will see investments concentrated on preserving the condition of the highway.
Minor improvements may also be considered but moderate improvements and/or
capacity expansion are not considered.

Reconstruction Corridor - Fundamentally similar to the "preservation"
corridor. What sets the "reconstruction" corridor apart is the need for
significant pavement and/or bridge reconstruction in order to bring the
condition of the roadway up to current standards. Does not include overall
capacity expansion.

Management Corridor - "Management" corridors include provisions for
preservation of the corridor, but exhibit enough safety or operational
performance problems to where moderate improvements to improve safety or
mobility are needed. Common improvements include the various forms of
"access management" improvements. Minor capacity improvements may be
considered, but major capacity expansion is generally not considered due to
financial constraints or lack of need. Corridors that have considerable
safety and/or mobility issues, as well as corridors that have a major capacity
need but lack the funding for capacity expansion, are commonly designated as
"management" corridors.

Expansion Corridor - The last of the four long-range investment
strategies, "expansion" corridors are those corridors where significant capacity
expansion is planned.

Turnback - Not an "investment strategy" per se, though sometimes
applied as one. MnDOT's districts will sometimes identify a given state
highway route as a "turnback candidate", which means the route is a candidate
for decommissioning with control of the route reverted to the city and/or county
in question. Some recent examples of highways that were "turned back" in
the Twin Cities metro are MN 288 in Anoka (which served the Anoka Treatment
Center), MN 101 through most of Hennepin County, and parts of MN 120 and MN 244
in the eastern metro.

Access Management - "Access management", as defined by MnDOT, is the
planning, design, and implementation of land use and transportation strategies
that manage the flow of traffic between the road and surrounding land. It
consists of various low- and mid-cost improvements to improve and/or channelize
traffic flow along a highway. Adequate spacing and appropriate design of
intersections, along with construction of frontage roads or consolidated
driveways for private access, are examples of access management. MnDOT has
a full resource page on the
topic.

Super-2 - MnDOT's definition of a "Super-2" is basically
equivalent to that of a 2-lane expressway. Wide shoulders, turn lanes
(including left turn lanes), passing lanes in selected locations, current
geometric standards, and high design speed. A "Super-2" may or may not
have partial control of access. My term for this is an "Improved-2", as I
consider a "Super-2 expressway" to have partial- or limited-access (i.e. no
private access points).

SPUI - Stands for Single-Point Urban Interchange. A
modified form of a diamond interchange where all four ramps come together at a
single intersection instead of at two separate intersections. Traffic
operations are improved both due to having only a single traffic signal as well
as requiring only a 3-phase timing for that signal. SPUIs are more
efficient than a standard diamond and can fit into a tight ROW, but the extra
bridging and retaining walls required drives their cost up considerably.

HOV-x - Stands for High Occupancy Vehicle. Usually applies to a
special freeway lane which is reserved for use by buses, motorcycles, and
passenger vehicles carrying the required number of passengers. The "x" in
the acronym defines the minimum number of vehicle occupants needed to satisfy
the HOV requirement. Most HOV lanes across the U.S. are HOV-2, meaning at
least two people in the vehicle (one of which is the driver, of course) are
needed to satisfy the HOV requirement.

HO/T - Stands for High Occupancy/Toll. This is a specialized
form of HOV lane where single-occupancy vehicles or vehicles not meeting the
minimum occupancy requirements for HOV can pay a toll to use the lane.
The lanes are still free for valid HOV vehicles. They are often called
"Lexus Lanes" by critics. Within Minnesota, the I-394 express/toll lanes
are considered to be HO/T lanes.

EIS - Short for Environmental Impact Statement. A project
document that looks at all reasonable and feasible alternatives, and the social
and environmental impacts of those alternatives, as part of the process for
selecting an alternative and design for a given project. Is generally
split into a Draft EIS and a Final EIS. The Draft EIS documents all the
alternatives for a given project, while the Final EIS provides further
documentation and study of the "preferred alternative".

NAIP - National Agriculture Imagery Program. A program of the
U.S. Department of Agriculture that develops and makes available aerial imagery
of much of the U.S. on a regular basis, often annually. This imagery is
made available in MrSID (short for multiresolution seamless image database)
format. MrSID data can be viewed via a plug-in (LizardTech
makes a free plug-in), or can be imported into a GIS platform such as
ArcGIS for further analysis. I have used
NAIP imagery to create several maps on my pages, and have also used it to show
aerial views of several route termini and Twin Cities area interchanges.